1. Field of the Invention
The present invention relates to a semiconductor device having a portion indicative of identification data such as a lot number.
2. Background Art
Semiconductor devices have formed on their surface a portion indicative of identification data such a lot number, a wafer address, or a serial number, which portion is hereinafter referred to as an ID-indicating portion. The ID-indicating portion is used to manage the process histories, etc. of semiconductor devices.
The ID-indicating portion is formed on the so-called ineffective region of the semiconductor device. An ineffective region is an area formed around the outer circumferences of the electrodes and circuit patterns of a semiconductor device to protect these components. The area of the ineffective region is typically small in order to reduce the size of the semiconductor device. Japanese Laid-Open Patent Publication No. 2004-72075 discloses a semiconductor device in which an ID-indicating portion is formed on the ineffective region.
The smaller the area of the ineffective region, the smaller the ID-indicating portion which can be formed thereon. It should be noted that ineffective regions are usually relatively small in area, as described above. This means that it is difficult or impossible to form a large ID-indicating portion on an ineffective region. If the ID-indicating portion formed on the ineffective region is small, its visibility is low (i.e., it is hard to visually recognize the ID represented by the ID-indicating portion), thus making it difficult to manage the process histories of semiconductor devices.